The invention relates to a component carrier for an electronic component, said component carrier being made in one piece of a metal sheet material and provided with means for surface mounting on a printed circuit board (PCB) and with holding flanges for holding an electronic component.
From DE-A1-43 32 770 a component carrier of this type is known, said component carrier being made in one piece of a highly thermally conductive material, such as metal, in order to obtain a good heat dissipation from the component, e.g. a power component, mounted in the component carrier. The component carrier is provided with a bottom plate from which holding flanges and an end stop extend. A component can be slid under the holding flanges until the end stop is reached. The component carrier may be surface mounted on the PCB.
U.S. Pat. No. 4,273,399 discloses another component carrier. This component carrier can be made from one piece of metal sheet material that is punched and formed. The component carrier is mountable on a PCB via solder tabs provided at the base of the component carrier. Holding notches are provided in the upper edges of sheet parts that extend perpendicular to the PCB. The component to be carriedxe2x80x94a disc-like piezo-electric tone transducerxe2x80x94is to be snapped in between opposing holding notches. When mounting the component, the parts comprising the holding notches flex outwards exerting moments of force to the solder connections between the component carrier and the PCB.
U.S. Pat. No. 4,663,695 discloses yet another component carrier made in one piece of metal sheet material. This component carrier is U-shaped and provided with solder tabs at one end of the U for mounting on a PCB. A component, e.g. a crystal resonator, is mountable in the U-shaped component carrier that holds the component in place between the two legs of the U. Due to the design of the component carrier, the component has to be mounted in the component carrier before it is soldered it to the PCB; hence this component carrier is not suitable for mounting and dismounting a component once it has been soldered to the PCB.
When mounting a component or a component carrier to a PCB by surface mounting, a small amount of soldering material is used, in contrast to mounting by solder tabs extending through holes in the PCB in which a relatively large amount of soldering material is used. Components or component carriers mounted by the surface mounting method are therefore more sensitive to loosening than components or component carriers mounted by way of solder tabs.
The surface mounted component carrier disclosed in DE-A1-43 32 770 is soldered to the PCB at its sides. However, when mounting the component the flanges at the sides are bent outwards, exerting stress on the solder joint. Over time the solder tin creeps and if the solder joint is exposed to a static load there is a risk that the component carrier drops off.
The risk of solder joint failure is even bigger when the component to be mounted is a dynamic component, such as a loud speaker, a microphone, a vibrator, a buzzer, etc.
The object of the present invention is to provide a component carrier that is surface mountable and in which the risk of dropping off due to solder joint failure is minimized.
This is achieved by providing the component carrier mentioned in the opening paragraph with a base provided with a central soldering platform for surface mounting on the PCB and with holding flanges extending from the base and connected to the base via tongues of the metal sheet material, said tongues extending in a plane parallel with the base.
Such a component carrier is soldable to the PCB at its central soldering platform, which is a part of the base. When the component carrier is soldered to the PCB, the holding flanges are allowed to flex out substantially without stressing the solder joint due to the flexible tongues connecting the holding flanges to the base. Therefore, a component can be mounted in the component carrier without detrimentally stressing the solder joint.
In a preferred embodiment the holding flanges extend substantially perpendicular to the base and each of at least two opposing holding flanges is provided with an inwardly extending collar for holding a part of the electronic component between said collar and said base. If the component has a shape that is engageable with the collars of the component carrier, this embodiment provides for a simple mounting and holding operation of a component, since no further mounting means is necessary.
The collar can be a rolled upper part of the respective flange giving the edge of the collar a rounded shape which allows an edge of the component to be snapped over the edge of the collar. This embodiment also allows for easy dismounting of a component due to the rounded edge of the collar.
Alternatively, the collar can be made as a simple angulation of the upper part of the respective, flange. This makes the manufacturing of the component carrier simple and the component can be mounted in the component carrier by sliding thereof under the collar.
In a preferred embodiment the component carrier has a generally rectangular shape and the tongues extend from the base to the corners of the component carrier. This configuration of the component carrier makes it suitable for a number of components and imparts high flexibility to the component carrier.